ABSTRACT/SUMMARY ? Animal Core-001 Age-related hearing loss (ARHL) ? presbycusis ? is a significant Public Health issue and the number one communication disorder and neurodegenerative condition of our aged population; and ranks as one of the top three chronic medical conditions, along with arthritis and cardiovascular diseases. Although much has been learned, the search is on for biomedical treatments that prevent, slow down or reverse the consequences of ARHL. In fact, there are no FDA-approved drugs to treat sensorineural hearing loss, despite a prevalence of over 40 million people in the US alone. Furthermore, approximately 30% of those listeners complain of tinnitus, i.e., sound perception in the absence of acoustic stimulation. The scope of the Animal Core will support the other projects to delineate the functional effects on neural correlates of complex sound processing using different modulators of presbycusis. More specifically, Core-001 (Animal Core) of this Program Project is responsible for obtaining, maintaining, and aging mice and rats; and in a timely manner provides experimental subjects for Projects 2-4 and Core-002. As such, the Animal Core is organized to achieve the following objectives: Purchase and maintain breeding colonies of mice and rats; To raise healthy animals in an optimal environment for research on the aging auditory system; To perform special procedures such as identification tagging and tattooing, diagnostic audiometry, obtaining tissue samples and gathering baseline information from animals; Perform diagnostic auditory brainstem response (ABR) audiometry to establish the hearing thresholds of subjects before (both acute and longitudinal) and during (longitudinal) experiments; and to maintain a secure database of vital information about colony animals, including birth dates, lineage, ABR audiometry test dates and results, and an experimental procedure log.